Vane displacement pumps or motors



March 15, 1960 C. s, PRENDERGAST v2,928,350

VANE DISPLACEMENT PUMPS OR MOTORS Filed Jan. 22, 1958 2 sheets-sheet 1 Inventor Ewell A Home)1 March 15, 1960 c. s. PRENDERGAST- 2,928,350

` VANE DISPLACEMENT PUMPS 0R MoToRs Filed Jan. 22, 1958 2 sheets-sheet 2 Hy. Z

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75 /05 a Val 7a /9 Zw/ 5 M Z5 By gri e Altorney Charles Scott Prendergast, Shoreham by Sea, England' Application January. 22, 1958,-,Serial No. 710,574

Claims priority, application- Great Britain Augustl, 195.7

2 Claims. (Cl. 103;-4)

This invention relates to that type ofl pump or motor in which at least one circular rotor carrying, a plurality of slidable vanes rotates inside the. bore. of a stator element, which bore may be circular in shape` andeccen trically disposed in relation to the rotor or, alternatively, may be of oval or other suitable shape..

It is known to cut in the side members of such a pump or motor, channels that connect with the bottoms ofv the grooves in the rotor in which the vanes are accommodated for sliding movement, thereby to providexfor pressure sealing on the pressure side and for filling the spaces at the bottoms of the groovesv on the. non-pressure or suction side. It is also known that such. channels. provide leak paths that greatly reduce the etciency of the pump or motor. v l

The present invention provides an. improvedy construction in which provisionv is made for maintaining effective sealing contact between the slidable vanes and the. stator bore.

A pump or motor embodying the inventionv may have one or more rotors and a corresponding number of stators as aforesaid and may be constructed for constant or variable displacement.

In a conventional pump or motor of the stated. type the or each rotor has a plurality of radial grooves ex.- tending inwardly from the periphery in which the vanes are slidable and equally angularly spaced. from one another.

As distinct from this the present invention provides a rotary pump or motor comprising at least one stator having a bore, inlet andl outlet. connections iny communication with said stator bore and separated from one another by unbroken. circumferential portions of said stator bore; a rotorv mounted for rotation within. said stator bore, said rotor having a plurality of equallyy angularly spaced pairs of straight-sided peripheral grooves the grooves of each pair diver'ging inwardlyv from the rotor periphery and being located closely adjacenty to one another relative to the angular spacing 'of the pairs of grooves, said last recited spacing being less than the angular length of each unbroken circumferential'por'tion of said stator bore, and a plurality of pairs'of flat vanes slidable one vane in each of said grooves thereby forming between adjacent pairs of said vanes, chambers acting alternately as pressure and non-pressure chambers -as the rotor rotates; said rotor also having a separate duct for each groove connecting the bottom thereof with the rotor periphery between the vane in said groove: and the vane in the nearest groove of the -adjacent pair of grooves, whereby on rotation of said yrotor one vane at a time of each pair of vanes makes sealing contact with said stator bore by uid pressure while traversing the unbroken circumferential portions of said'bore.

This construction ensures that when the rotor rotates, one of each pair of the vanes that'separate the pressure chambers from the non-pressure chambers is held in sealing contact with` the stator bore; and it also ensures the tilling of the spaces at the bottoms 'of the grooves tes Patat 2 behindthe vanes with fluid as the vanes move outwards onthe non-pressure side ofthe rotor. This eliminates thenecessity for the aforesaid channels inthe. side mentbersofthe pumpV or motor and their attendant leak paths.-

The invention will be fully'understood from. the fore.- going together with the further description that follows, and the accompanyingdrawings Whereon, by way of ex.- ampl'e, one construction form. of. the rotor. is appliedA to a pump having features protected by our co-pending application No. 710,573. Y Y

Fig. 1 ofthe drawings represents across sectionV of the pump on the line I--I of.Fig.-2.

Fig. 2 representsr a longitudinal section on theI line II-II of Fig. 1. f Y

Fig. 43 represents.` a longitudinal section on the line. Ill-III? of Fig. 11.

Fig. 4 represents across sectionin either of the planes IVe-IV of Fig. 3.

As illustrated, a. driving shaft. 1 is carried in ball-bearings 1A housed inend. members 2 and 3. Keyed to the7 driving shaft., concentrically in relationl to its axis, are three circular rotors 4, 5 and 6 the rotor 6 beingequaly in `width to the other two. The rotors 4V and S- are adja'.- cent to the end members 2 and 3 respectively and are separated from the intermediate rotor 6 by two parti-` tioning members 7. and 8. The partitioning members 7 and18 have annular grooves 7A and 8A. formed around their peripheries and. t inside surrounding members 7B and SB off the same axial; width as said partitioning members, so that the annular. grooves 7A and- 8A'. are completely enclosed. The rotors 4 and 5 are contained in the circular bores of stator members 9 and: 1.0, and the bores ot'. these stator members have equal and fixed eccentricities in relation to the axis of the driving shaft 1. The stator members 9 and 10, have partly annular grooves 9A- and 10A, Figs. 3 andV 4, formed around their peripheries over an angular distance vof about and tit inside surroundingmembers 9B and 10B of the same axial widthv as said, stator members, so that the partly annular grooves 9A and 10A are completely enclosed. The intermediate rotor 6 is contained in the circular bore of a stator member 11 which. itself is slidably mounted in slides 12A formed in a surrounding member 12. Theposition of the stator member 1.1 can be adjusted in the slides 12A by anadjusting screw 13 and nut 14. By means of this adjustment the stator 11 can be movedV in relation to the axis ofthe driving shaft 1 so as to bringtheboreof the stator 6` to any position between one of lmaximum eccentricity in one direction and one of vmaximum eccentricity in the oppositevdirection in relation to said. axis. The diameters of the bores of all the stator members 9, 10. and 11 are sufficiently greater than the outside diameters of the ,rotors 4, 5 and 6 to afford eccentricity.

All the stationary members 2 9, 9B, 7, 7B, 12, 8, 8B, 10, 10B and 3 are secured rigidly together by bolts 23.

In each of the: rotors are formed eight equidistantly spaced pairs of straight-sided grooves 15, the grooves of f each pair diverging inwardly from the rotor periphery and being located closely adjacent to one another relative to the angular spacing of the pairs Aof grooves, which angular spacing isless than the angular length of each unbroken circumferential portion of the stator bore. Sixteen, or a multiple of sixteen, radial ducts` 15A connect 'the bottoms of all the grooves 15 of the rotor periphery between adjacent ,pairs of said grooves. Slidably mounted in each groove 1S therey isa vane 16` the outer end of whichis shaped to conform approximately with the shape of the periphery of the bore of the pertaining stator. When the, shaft 1,'is rotated. the vanes .in lthe rotors 4, 5 and 6 are brought into contact with-the peripheries of the bores of the surrounding stators 9,

rotor form with the periphery of the rotor and the' bore of the corresponding stator and the side or partitioning members, eight enclosed.arcuateohambern4 and these chambers expand and contract inA volume as the rotor is rotated.

The fixed stators 9'and 10 have arcuate `grooves 9C,Y

9D, 10C and 10D formed in the peripheries of their bores, the two grooves in each stator being diametrically opposite to one another. Each of the arcuate grooves 9C and 10C is connected to one extremity of each of the partlyannular grooves 9A and 10A.V The other extremities of the partly annular grooves 9A1and 10A are connected by radial holes 17 and "18 inthe surrounding members .9B and 10B to anaxial [hole 19 which passes throughlthe members 7B andSB and the member 12 surrounding the intermediate stator 11. screw-threaded inlet port 20 formed in the member 12 connects to the axial hole 19." When the shaft 1 is rotated, the expanding chambers of the 'rotors 4 and 5 are filled with fluid fed from the inlet port :20 into thel arcuate grooves 9C and 10C. The contracting chambers connect with the arcuate grooves9DA and 10D. The adjustable stator 11 has two enclosed radial grooves 11A and 11B which pass through it and connect to two further arcuate grooves 12B and 12C in the slide 12A of the surrounding member 12. The area of the mouth of each of the grooves 12B and 12C is slightly less than the projected area of half the periphery of the bore of the stator 11, thus ensuring that the slide forms a seal by means of fluid pressure. The grooves 11A and 11B are on the same diametral centre line as the grooves 9C and 9D and the grooves 10C and 10D, but the grooves 11A and 11B are at 180 to the'grooves 9C and 10D and the grooves 11B and 12CY are at 180 to the grooves 9D and 10D. Radial screw-threaded ports 21 and 22 formed in the memberV 12 connect 'respectively with the grooves 12B and 12C, o Grooves9D and 10D are connected respectively to the enclosed annuli 7A and 8A formed in the partitioning members 7 and 18. The annuli 7A and 8A are also connected to the groove 12C. When the shaft is rotated theiluid displaced by the contracting chambers ofthe rotors 4 and 45 passes through the grooves V9D and 10D around the annuli 7A and 8A into the radialgroove 12C and thence through the outlet port 22,. f When the relative eccentricty of the stator 11 and the rotor 6 is opposed to the relative eccentricity of the sta/tors 9 and 10 and the rotors 4 and 5, fluid is fed in through the port 21 to the expandingchambers' of the rotor 6, and the fluid displaced by the contracting chambers of said rotor 6 is addedto that displaced by the contracting chambers of the rotors 4 and `5, the total ilowpssing out through lthe outlet port 22.

When there is no relative eccentricity between the stator 11 andV the rotor 6, no displacementtakes place between them and under thisA` condition the total disare always kept in contact with the bore of each stator vby fluid pressure between the expanding and contracting 15A Vat opposite sides of the rotor are always subjectto` pressure, the pressure moving from the groove 9D into Y a radial hole 15A` at the.. right in Fig..4 for projecting one of the vanes 16 into sealingcontact with the stator while at the same timeone of the vanesof the group of vanes 16 in theopposite side ofthe rotor is projected by pressure acting through a radial hole 15A at the left of the rotor ,in Fig. 4 for projecting the associated vane 16 into sealing relation with the stator.

The radial ducts '15A' also provide means for filling Y the spaces at the bottoms of the grooves 15 with fluid as the vanes 16 move outwards and for displacing this uid as the vanes'move inwards.

reciprocaton of the vanes and adds to the fluid Vdisplacement caused by the sweeping action of the vanes,the piston displacement'caused by the reciprocating moveinentsofthevanes. o I`wish it to be understood thatthe invention is not restricted to a pump as herein described since rotors cons tructed'in accordancewith the invention may be incorporated in various pumps or motors of thetype `first set forth herein.

Iclaim: o j 1. Ajrotary pump ormotor comprising at least one stator having `a bor'e;`inlet *andoutlet connections in communication` withsaid stator bore and separated from one another by t'wo unbrokenv circumferential portions of said stator bore; a rotor mounted forrotation within `said stator bore, said rotor having ka `plurality of equally angularly'spaced pairs of straight-sided peripheral grooves, the grooves of each pair diverging inwardly from vthe rotor peripheryand being located closely adjacent to one anotherrelative to the angular1spacing ofthe pairsof grooves, said last recited spacingy beingrless than the angular length of each unbroken Vcircumferential portion of said stator bore; and apluralityof pairs of flat vanes slidableone vane in each of saidrgrooves thereby formingbetween Vadjacent pairsof said vaneschambers acting alternately as pressure and non-pressurechambers as the rotorrotates; said rotor also having a separate duct for each groove connecting the bottom thereof with the rotor periphery between the vane in saidrgroove Aand the vane in the nearest groove ofthe adjacentpar of placement of the pump is thatobtained from the dis;

placement chambers of only the rotors 4 and 5. When the relative eccentricityof the stator 11 and th 'rotor 6 is in the same-direction as the relative eccentricity of the stators 9 and 10 and the rotors'4 and 5, the displacement chambers ofthe rotor 6 absorb part oall the displacement of the rotors 4 and 5 according to thedegrees of eccentricity,'the fluid-` absorbed returning to supply` through Ythe Aport 21.Y 1 j. ,j 4 The grooves 9C and 9D inthe stator 9, the grooves 10C and 10D in the stator 10, andthe grooves V11A and 11B in the stator 11 areseparated Yfrom` one an-; other at each end byan langular distance slightly greater than the angular distanebetween any twoadjacentpairs f vanes 16 in the rotors 4, 5 and 6.1. By reason ofwthe radial holes 15A thatconnect the bottoms of the radial grooves, wherebyonrotation of said rotor, atleast ltwo vanes at a time, ofwhich" at least oneisjof a pair of two diametricallyopposite pairs of 'vanes,V makesealing contact at all times with said stator bore by uid pressure" thrusting said vanes outwardly intosealing relation with thefinnerY surface of the stator bore whiletraversing thevunbroken circumferential portions of saidbore.

2. A rotary pump or motor as `setforthjn claim' 1,

-including `a rotatably'mounted shaft having Ia plurality j of rotors. thereon, a similar numbenof `circularly bored -stators' surrounding: the rotors and Y"rrlounted eccentrically in relation Vto the axis'of-the` rotor shaft, said rotors having peripheralgrooves therein; vanes slidable in said peripheral grooves in the rotors thereby forming displacement chambers between the rotors and the stator bore, in-

' let and outlet Yconnections communicatingwith each ofV fthe stator fbores, means for interconnecting said'inlet connections, `means forinterconnecting said'outlet con nections, a member afiordinga slide f o'r one only of the statOrS, and means,` for displacing the slide-borne stator at will betweenfa positiononone `sidejo'f therotor shaft axis and a position anjequal distance. on theoopposite side of said axis ,thereby` to vary `the ecentricity of the bore 9i' the' slide-.borne stator.,

@asia-arg entre@ 'page 1 I Thisprovides la ,smooth References Cited 'in the le of this patent UNITED STATES PATENTS Charles Aug. 5, 1902 Blackmer Aug. 25, 1931 Rayburn Jan. 16, 1934 Ott Jan. 15, 1935 Hittell Dec. 1, 1936 Tucker Feb. 6, 1945 6 Brown July 4, 1950' Breedlove Feb. 13, 1951 Ungar Oct. 12, 1954 Miller et al. Oct. 2, 1956 Moore Aug. 27, 1957 FOREIGN PATENTS Great Britain of 1901 Australia Mar. 23, 1955 

